CASE 1264 Published on 31.01.2002

Myelolipoma of the adrenal gland: MR findings

Section

Uroradiology & genital male imaging

Case Type

Clinical Cases

Authors

F. Iafrate, P. Paolantonio, R. Ferrari, M. Danti, S. Visconti

Patient

48 years, male

Categories

No Area of Interest ; Imaging Technique MR

No Procedure ; No Special Focus ;

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Clinical History

The patient was admitted for characterisation of an adrenal mass incidentally discovered on US examination. The patient was completely asymptomatic and had no history of previous abdominal surgery.

Imaging Findings

The patient was admitted for characterisation of an adrenal mass incidentally discovered on US examination. The patient was completely asymptomatic and had no history of previous abdominal surgery.

MR examination was performed with an 1.5 T scanner (Magnetom Vision Plus, Siemens; Erlangen, Germany) equipped with a phased array body coil. The imaging procedure included the following sequences: T1-weighted FLASH sequences acquired on the axial and coronal planes, T1-weighted sequences with fat saturation, T2-weighted HASTE sequences and in-phase and opposed-phase sequences acquired on the axial plane.

MR examination showed a rounded mass of the left adrenal gland, 35 mm in diameter. This mass appeared heterogeneous, including tissues of different signal intensity: the mass had heterogeneous but high signal in T1-weighted images (TR 535 ms; TE 35 ms) within the bulk of the mass, consistent with fat (Fig. 1a). The signal intensity was also high on T2-weighted images (TR 2090 ms; TE 45 ms), following the signal characteristics of subcutaneous fat (Fig. 1b).

These radiological findings led to the diagnosis of left adrenal myelolipoma.

Discussion

Myelolipoma is an uncommon benign tumour composed of mature adipose cells and haematopoietic tissue. These tumours are usually discovered incidentally and are clinically silent; occasionally, large myelolipomas may also bleed spontaneously or cause pain. The fatty component is macroscopic in most cases and is virtually diagnostic when discovered on cross-sectional imaging. MR imaging can demonstrate fat within most myelolipomas. As expected, the fatty component of myelolipomas appears hyperintense on T1-weighted images and has intermediate signal intensity on T2-weighted images.

The non-uniform admixture of fat and bone marrow components often appears heterogeneously hyperintense on T2-weighted images (Figs 2a and 2b). The use of fat suppressed sequences is confirmatory, demonstrating a focal reduction in signal intensity in the fatty component of the mass. Although metastasis to the adrenal gland or primary adrenal cortical cancer may mimic this appearance, fat-containing malignancies are rare.

Differential Diagnosis List

Myelolipoma of left adrenal gland

Final Diagnosis

Myelolipoma of left adrenal gland

References

[1] Tanaka D, Oyama T, Niwotsukima, Nakajo M.
A case of asymptomatic giant myelolipoma of adrenal gland.
Radiat Med.1998 May-Jun;16(3):213-16. (PMID: 9716002)

[2] Casey LR, Cohen AJ, Wile AG, Dietrich RB.
Giant adrenal myelolipomas: CT and MRI findings.
Abdom. Imaging 1994 Mar-Apr;19(2):165-7. (PMID: 8199553)

[3] McLoughlin RF, Bibbey JH.
Tumors of the adrenal gland: findings on CT and MR imaging.
AJR Am Journ Roentgenol 1994 Dec;163(6):1413-18. (PMID: 7992738)

[4] Peppercorn PD, Reznek RM.
State of the art CT and MRI of the adrenal gland.
Eur.Radiol. 1997;7(6):822-36. (PMID: 9228096)

Case information

URL:	https://www.eurorad.org/case/1264
DOI:	10.1594/EURORAD/CASE.1264
ISSN:	1563-4086

Figure 1

Myelolipoma

MR scan: T1-weighted image acquired on the axial plane. The image shows a heterogeneously hyperintense bulky mass of the left adrenal gland.

MR scan: T2-weighted image acquired on the axial plane. The image shows the same mass seen in Fig. 1a, with a hyperintense appearance like the subcutaneous fatty tissue.

Figure 2

Myelolipoma